This invention relates to a semiconductor device and, more particularly, to a semiconductor device provided with a plurality of interconnection wirings arranged at a single level or a multilevel.
With scaling down of semiconductor device, not only circuit elements such as of transistors but also interconnection wirings are being scaled down. Especially, the space between the adjacent two interconnection wirings is reduced to a sub-micron level. The interconnection wirings thus formed is then subject to a thermal treatment to improve ohmic contacts between each element region and each associated wiring and between lower and upper wirings. Each interconnection wiring is made in general of aluminium (Al), and in that case the so-called hillocks occur or are produced on each wiring. The hillocks occur not only at the up-side surface of the wirings but also at the sidewall surfaces thereof. The hillocks on the sidewalls thus cause the short-circuit between the adjacent wirings.